Plug member and low-temperature storage

ABSTRACT

A plug member, which is to be used for a low-temperature storage including: a heat-insulating door to close an opening face of a heat-insulating housing; a cooling device; and a through-hole passing through a heat-insulating wall in the housing and having an internal thread on an inner periphery thereof, and which closes an opening portion of the through-hole on an outer side of the storage, includes: an external thread to be threadedly engaged with the internal thread; and a flange member to abut onto a face having the opening portion and close the portion, by threaded engagement between the external and internal threads, the external thread having a cut, which opens a part of the opening portion, formed in a portion of an outer periphery thereof, in a state where the flange member does not abut on the face, while the external thread is threadedly engaged with the internal thread.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Japanese Patent Application No. 2010-242447, filed Oct. 28, 2010, of which full contents are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plug member and a low-temperature storage.

2. Description of the Related Art

In a low-temperature storage to be used for storage of frozen goods, etc., or cold preservation of biological tissues and specimens, etc., air inside the storage is cooled, thereby occasionally bringing about a negative pressure state where atmospheric pressure inside the storage is lower than the atmospheric pressure outside the storage. Since the negative pressure state inside the storage makes it difficult to open a door of the low-temperature storage, the low-temperature storage is generally provided with a pressure adjusting device to resolve the negative pressure state inside the storage (e.g., Japanese Laid-Open Patent Publication No. 2010-25471).

In Japanese Laid-Open Patent Publication No. 2010-25471, a user removes a plug for closing a port for inflow of the air outside the low-temperature storage into the storage, thereby resolving the negative pressure state inside the storage. The user occasionally drops the plug, when removing the plug for closing the port. In such a case, depending on the installing location, structure, etc., of the low-temperature storage, it occasionally becomes burdensome for the user to pick up the dropped plug and close the port with the plug again.

SUMMARY OF THE INVENTION

A plug member according to an aspect of the present invention, which is to be used for a low-temperature storage including: a heat-insulating housing including an opening face; a heat-insulating door configured to open or close the opening face; a cooling device configured to cool an article stored inside the heat-insulating housing; and a through-hole passing through a heat-insulating wall included in the heat-insulating housing from an outer side of the storage to an inner side thereof and having an internal thread formed on an inner periphery thereof, and which is configured to open or close an opening portion of the through-hole on the outer side of the storage, includes: an external thread configured to be threadedly engaged with the internal thread; and a flange member configured to abut onto a face having the opening portion formed therein and close the opening portion, by threaded engagement between the external thread and the internal thread, the external thread having a cut formed in a portion of an outer periphery thereof, the cut configured to open a part of the opening portion in a state where the flange member does not abut on the face having the opening portion formed therein, while the external thread is threadedly engaged with the internal thread.

Other features of the present invention will become apparent from descriptions of this specification and of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For more thorough understanding of the present invention and advantages thereof, the following description should be read in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view illustrating a low-temperature storage 10 according to one embodiment of the present invention;

FIG. 2 is a perspective view illustrating a low-temperature storage 10 in a state where heat-insulating doors 21 and 22 are open;

FIG. 3 is a plan view illustrating a low-temperature storage 10;

FIG. 4 is a diagram illustrating an exploded pressure adjusting device 30 and a portion of a heat-insulating wall of a heat-insulating housing 20;

FIG. 5 is a diagram illustrating a state where members 60 and 61 are actually mounted onto a heat-insulating wall of a heat-insulating housing 20;

FIG. 6 is a perspective view illustrating a plug member 62;

FIG. 7 is a side view illustrating a plug member 62;

FIG. 8 is a cross-sectional illustrating a pressure adjusting device 30 in a state where a through-hole 80 is closed; and

FIG. 9 is a cross-sectional view illustrating a pressure adjusting device 30 in a state where a through-hole 80 is open.

DETAILED DESCRIPTION OF THE INVENTION

At least the following details will become apparent from descriptions of this specification and of the accompanying drawings.

An outline will now be described of a low-temperature storage 10 according to one embodiment of the present invention with reference to FIGS. 1 and 2. FIG. 1 is a perspective view illustrating the low-temperature storage 10 in a state where a heat-insulating door 21 is closed, and FIG. 2 is a perspective view illustrating the low-temperature storage 10 in a state where heat-insulating doors 21 and 22 are open. Here, it is assumed that an X-axis direction is a side-to-side direction relative to the low-temperature storage 10, a Y-axis direction is an up-and-down direction relative to the low-temperature storage 10, and a Z-axis direction is a fore-and-aft direction relative to the low-temperature storage 10.

The low-temperature storage 10 is configured to store frozen goods, etc., or preserve biological tissues, etc., in an ultralow temperature range lower than or equal to −85° C., for example, and includes a heat-insulating housing 20 including an opening face at the front thereof (+Z side).

The heat-insulating doors 21 and 22 configured to open or close the opening face at the front are provided on the opening face at the front of the heat-insulating housing 20, and a cooling device 23 configured to cool an inside of the storage is provided on the lower side (−Y side) of the heat-insulating housing 20. A pressure adjusting device 30 configured to resolve a negative pressure state inside the storage is provided on a side surface on the left-hand side (−X side) of the heat-insulating housing 20.

The heat-insulating door 21 is a so-called outer door and is provided with a control panel 31 that is configured to perform setting of the temperature inside the storage, and the like. A handle 32 configured to open and close the heat-insulating door 21 is provided at the left edge of the heat-insulating door 21. A lock member 33, which is configured to fix the heat-insulating door 21 together with the handle 32 when the heat-insulating door 21 is closed, is provided on the side surface on the left-hand side of the heat-insulating housing 20. The heat-insulating door 22, which is configured to enhance the heat-insulating properties inside the storage, is provided inside the heat-insulating door 21 as an inner door.

FIG. 3 is a plan view illustrating the low-temperature storage 10. The heat-insulating housing 20 includes a metallic inner case 40, a metallic outer case 41 provided such that the inner case 40 is covered, and a heat-insulating material 42 filled between the inner case 40 and the outer case 41 so as to enhance the heat-insulating properties, for example. The inner case 40 and the outer case 41 have an opening face, at the front, so that the frozen goods, etc are taken out and put in.

The heat-insulating door 21 is a metallic door whose inside is filled with a heat-insulating material 45. Packing 46, which is configured to enhance airtightness inside the storage when the heat-insulating door 21 is closed, is provided at the inner periphery of the heat-insulating door 21. The low-temperature storage 10 becomes in a hermetically-sealed state when there is no air to enter and exit in the pressure adjusting device 30 while the heat-insulating doors 21 and 22 are closed.

The pressure adjusting device 30 will be described in detail with reference to FIG. 4. FIG. 4 is a perspective view illustrating the exploded pressure adjusting device 30 and a portion of a heat-insulating wall of the heat-insulating housing 20 on which the pressure adjusting device 30 is mounted.

A through-hole 50, which passes through the heat-insulating wall from the outside of the storage to the inside thereof, is formed in the heat-insulating wall of the heat-insulating housing 20 on which the pressure adjusting device 30 is mounted. The pressure adjusting device 30 is inserted into the through-hole 50 and includes members 60 and 61 configured to form a path for the air outside the storage to flow into the storage, and a plug member 62 configured to open or close the path for inflow of the air.

The member 60 is a flanged tubular member to be inserted into the through-hole 50 from the inside of the storage, and includes a cylindrical member 70 with an external thread formed on the outer periphery thereof and a flange member 71 that is integrally formed on one end of the cylindrical member 70.

The member 61 is a flanged tubular member to be inserted into the through-hole 50 from the outside of the storage, and includes a cylindrical member 72 and a flange member 73 that is integrally formed on one end of the cylindrical member 72. On the inner periphery of the cylindrical member 72, such an internal thread is formed as to be threadedly engaged with the external thread formed on the cylindrical member 70.

FIG. 5 is a diagram illustrating a state where the members 60 and 61 are actually mounted onto the heat-insulating wall of the heat-insulating housing 20. By threaded engagement between the external thread of the cylindrical member 70 and the internal thread of the cylindrical member 72, the flange member 71 abuts onto the wall surface of the inner case 40 from the inner side of the storage, and the flange member 73 abuts onto the wall surface of the outer case 41 from the outer side of the storage. Thus, the flange members 71 and 73 are joined to each other in such a manner as to press the heat-insulating wall of the heat-insulating housing 20 from both the inner side and the outer side of the storage. A through-hole 80, which is configured to pass through between the inner side of the storage and the outer side thereof, is formed inside the cylindrical members 70 and 72 as the path for inflow of the air.

The plug member 62 is a member configured to open or close an opening portion 81 of the through-hole 80 on the outer side of the storage, and includes an external thread 75, a knob 76, and packing 77 as shown in FIG. 6. The knob 76 and the packing 77 correspond to a flange member. FIG. 6 is a perspective view illustrating the plug member 62 and FIG. 7 is a side view illustrating the plug member 62.

As shown in FIG. 4, the external thread 75 is a column thread configured to be threadedly engaged with the internal thread of the cylindrical member 72. On the outer periphery of the external thread 75, a plurality of cuts 100 a to 100 d are formed along the direction of the threaded engagement of the external thread 75. A length of the cuts 100 a to 100 d is substantially equal to a length d of the external thread 75 shown in FIG. 7. Therefore, the cuts 100 a to 100 d are formed over the entire length of the external thread 75 in the threaded engagement direction. In an embodiment of the present invention, the external thread 75 is formed such that the cuts 100 a to 100 d, which are equal in shape, are provided at regular intervals in the outer periphery of the external thread 75.

The knob 76 is formed at one end of the external thread 75 integrally therewith, and is in a columnar shape with a diameter greater than that of the external thread 75, for example. The packing 77 is pasted to a face of the knob 76 on the external thread 75 side, along the outer circumference of the external thread 75.

With the external thread 75 being threadedly-engaged with and screwed into the internal thread of the cylindrical member 72, the packing 77 abuts onto a face around an opening of the flange member 73 (the face having the opening portion 81 formed therein). Therefore, as shown in FIG. 8, the plug member 62 securely closes the through-hole 80, which prevents the cool air from leaking from the inside of the storage to the outside thereof. FIG. 8 is a cross-sectional view illustrating the pressure adjusting device 30 in a state where the through-hole 80 is closed (cross-sectional view of the cross section along a line A-B of FIG. 3, when viewed in the −Z direction). Herein, only the cut 100 a out of the cuts 100 a to 100 d in the external thread 75 is illustrated for easy understanding of cross-sectional structure of the pressure adjusting device 30.

FIG. 9 is a cross-sectional view of the pressure adjusting device 30 in a state where the through-hole 80 is open. FIG. 9, similarly to FIG. 8, is a cross-sectional view of the cross section along the line A-B of FIG. 3, when viewed in the −Z direction. When the plug member 62 is rotated to loosen the external thread 75, the packing 77 is brought to a state where it does not abut on the face around the opening of the flange member 73. In a state where the external thread 75 is loosened, a part of the external thread 75 is threadedly engaged with the internal thread of the cylindrical member 72. In such a state, there is nothing blocking a space between the cut 100 a and a part of the opening portion 81, for example. Thus, for example, when the inside of the storage is in a negative pressure state, loosening of the external thread 75 enables an inflow of the air outside the storage into the storage. That is to say, the negative pressure state can be resolved by loosening the external thread 75.

Hereinabove, a description has been given of the low-temperature storage 10 according to an embodiment of the present invention. Since the external thread 75 of the plug member 62 has the cuts 100 a to 100 d formed therein, the negative pressure state inside the storage is resolved without the plug member 62 being removed, in an embodiment of the present invention. As a result, the possibility is decreased that the plug member 62 is dropped when the negative pressure state is to be resolved, thereby being able to reduce the burden of the user. Furthermore, for example, in a case where the user has the low-temperature storage capable of resolving the negative pressure using the plug member without cuts, if only the plug member 62 with the cuts is newly provided, a similar effect to that in an embodiment of the present invention can be achieved without any special work, etc.

For example, in place of the external thread 75, an external thread with the cuts provided in a cylindrical member can also be used. The external thread with the cuts provided in a cylindrical member, however, might have component strength, as the external thread, lowered since the inside of the cylindrical member is hollow. In a case of the external thread 75, the column member is used instead of the cylindrical member, thereby being able to enhance the component strength of the external thread 75.

For example, even if the cuts in the external thread 75 are formed only in a portion of the external thread 75, the similar effect can be achieved to that in an embodiment of the present invention. However, in a case where the cuts are each formed only in a part from a tip edge of the external thread 75 (the edge on the side opposite to that of the knob 76), for example, there is a possibility that the user may turn the knob 76 too much, in order to get communication between the inside and the outside of the storage, thereby removing the plug member 62. In the case of the external thread 75, the cut 100 a is formed over the entire length of the external thread 75 in the direction of the threaded engagement. This enables the user to securely resolve the negative pressure state simply by turning the knob 76 slightly to loosen the external thread 75.

The external thread 75 has four cuts 100 a to 100 d formed therein. Thus, the negative pressure state can speedily be resolved as compared with a case of the external thread having only one cut, for example.

For example, the through-hole configured to communicate between the inside and the outside of the storage can be formed in the heat-insulating door 21 at the front of the low-temperature storage 10. The heat-insulating door of a common low-temperature storage, however, is of a dual structure (structure including the inner and outer doors) similarly to that in an embodiment of the present invention. This makes the structure of the low-temperature storage complicated when the through-hole is formed at the front. In the low-temperature storage 10, the through-hole 80 is formed in the heat-insulating wall on a side surface of the heat-insulating housing 20, thereby being able to make the structure of the low-temperature storage 10 a simple structure with the convenience for the user being secured.

The above embodiments of the present invention are simply for facilitating the understanding of the present invention and are not in any way to be construed as limiting the present invention. The present invention may variously be changed or altered without departing from its spirit and encompass equivalents thereof. 

1. A plug member to be used for a low-temperature storage including: a heat-insulating housing including an opening face; a heat-insulating door configured to open or close the opening face; a cooling device configured to cool an article stored inside the heat-insulating housing; and a through-hole passing through a heat-insulating wall included in the heat-insulating housing from an outer side of the storage to an inner side thereof and having an internal thread formed on an inner periphery thereof, the plug member configured to open or close an opening portion of the through-hole on the outer side of the storage, the plug member comprising: an external thread configured to be threadedly engaged with the internal thread; and a flange member configured to abut onto a face having the opening portion formed therein and close the opening portion, by threaded engagement between the external thread and the internal thread, the external thread having a cut formed in a portion of an outer periphery thereof, the cut configured to open a part of the opening portion in a state where the flange member does not abut on the face having the opening portion formed therein, while the external thread is threadedly engaged with the internal thread.
 2. The plug member of claim 1, wherein the external thread is a thread having the cut formed in a portion of the outer periphery of a column member.
 3. The plug member of claim 1, wherein the external thread has the cut formed over an entire length thereof in a direction of the threaded engagement.
 4. The plug member of claim 2, wherein the external thread has the cut formed over an entire length thereof in a direction of the threaded engagement.
 5. The plug member of claim 3, wherein the external thread includes a plurality of cuts as the cut.
 6. The plug member of claim 4, wherein the external thread includes a plurality of cuts as the cut.
 7. A low-temperature storage comprising: a heat-insulating housing including an opening face; a heat-insulating door configured to open or close the opening face; a cooling device configured to cool an article stored inside the heat-insulating housing; a through-hole passing through a heat-insulating wall included in the heat-insulating housing from an outer side of the storage to an inner side thereof and having an internal thread formed on an inner periphery thereof; and a plug member including an external thread configured to be threadedly engaged with the internal thread and a flange member configured to abut onto a face by threaded engagement between the external thread and the internal thread, the face having an opening portion formed therein of the through-hole on the outer side of the storage, the plug member configured to open or close the opening portion, the external thread having a cut formed in a portion of an outer periphery thereof, the cut configured to open a part of the opening portion in a state where the flange member does not abut on the face having the opening portion formed therein, while the external thread is threadedly engaged with the internal thread.
 8. The low-temperature storage of claim 7, wherein the through-hole is formed on the heat-insulating wall on a side surface of the heat-insulating housing. 